Mechanical stoker



(No Model.)

I. H. DAVIS.

UNITED STATES APMFENT OFFICE.

ISAAC H. DAVIS, OF BOSTON, MASSACHUSETTS.

MECHANICAL STOKER.

SPECIFIGATION forming part of Letters'Patent No. 412,241, dated October 8, 1889.

Application filed April 22, 1889.

To asZZ whom it may concern:

Be it known that ILISAAC H. DAvIs, of Boston, in lthe county of Suffolk and 'State of Massachusetts, have invented certain new and useful Improvements in Mechanical Stokers, of which the following, taken in connection with the accompanying drawings, is a specification.

Myinvention relates to 'improvements in mechanical stokers in which the shovel or beater is hinged or has its fulcrum at the bottom,instead of at the top, as is usually the case, and provided with longitudinal corrugations to hold the coal deposited on the face of the shovel at different distances from the fulcru ni, so that portions of the coal have greater or less force imparted to them than others; and it also consists in further improvements hereinafter described and claimed.

The objects of my improvements are, first, to provide a means of evenly distributing a limited quantity of coal over the fire-surface of a furnace at regular and frequent intervals second, the construction of an apparatus for this purpose which can be readily applied to already-existing boiler-fronts without disturbing or altering them to any material eX- tent; third, the construction of an apparatus for this purpose which will admit of the furnace-doors being opened to trim the fire, or in case of an accident happening to the mechanism of the stoker to admit of the fire being fed in the ordinary manner. I attain these objects by the mechanism illustrated in the accompanying drawings, in whioh Figure 1 is a Vertical elevation of a hoilerfront, showinga stoker applied to each of the two doors. Fig. 2 is avertical section through the center of one of the stokers on the line o 'v, Fig. 1, at the termination of its throw. Fig. 3 is a Vertical section through the center of one of the stolcers at the beginning of its throw and at the time of its receiving its charge of coal from the hopper. Fig. 4 is a front elevation of Fig. 3 in same position and show ing slotted connection to the tumbler-shaft in section. Fig. 5 is a perspective view of one of the shovels, showing its connection to the slotted tumbler-shaft. Fig. 6 is a section through the slotted end of the tumbler-shaft and squared end of shovel-shaft, on the lines Serial No. 308,233. (No model.)

a: x of Fig. 4, and shows a side view of the cam and pawl which operate the shovel.

Similar letters refer to similar parts throughout the several views.

The accompanying drawings show two doors, with the aetuating mechanism located between them. It is ohvious, also, that my device may be applied to furnaces having one door only, or having two or more.

The frames or plates A, carrying the shovels and their inclosing-casings, are made right and left hand and of a general form corresponding to an ordinary furnace-door, having hinges to fit the lugs which carry the ordinary door on the boiler-front, and latches a a' to fasten these doors or plates shut. Mounted upon these plates Aare the inclosing-casings o B and the shovels O, which are pivoted upon the shafts c, located at the bottom of the shovel and having their inner ends squared, so as to be turned by the correspondinglysocketed ends of the tumbler-shaft D. The shovels are provided with a long lip or shelf O at the bottom, giving them a general Shape when viewed in cross-section, corresponding to that of a capital letter L, which is designed to prevent any of the coal deposited on the face of the shovel from falling in a heap on the bottom of the casing B, and thereby preventing the practical working of the stoker. These ends on the tumbler-shaft D at the point marked d are slotted outwardly, so that the squared ends of the shaft c' can be drawn out from them laterally by opening of the door A. On the tumbler-shaft D is attached a combined lever and pawl E, which is actuated by the cam F, with which it engages, and which is located j ust below it upon the cam-shaft G. At the upper part of the pawl E is hinged at ma rod e, carrying a spring c', and passing at its upper end through a lug 82, which is fastened to the boiler-front.

The cam F, rotating slowly, lifts the pawl E and compresses the spring e', forcing the rod e upward through the lug eg, at the same time causing the shovel C to rotate on its fulcrum until the lip 02 of the shovel is brought to the inner edge h of the delix-'eryspout from the hopper.

On the cam F, at the point markedf, there is a. slight and sudden enlargement, now

causing this edge of the shovel 02 to be suddenly thrown back to the outer edge b' of the deliVery-spout, allowing a small amount of coal to be deposited on the face of the shovel through the spout. The shovel is then suddenly released by the point of the cam F clearing the pawl E, and allowing the spring c' to throw the shovel suddenly forward, when the washer K, upon the end of the rod e, above the lug 82, arrests it in the position shown in Figs. 1 and 2. This operation is repeated at regular and frequent intervals. Upon the cam-shaft G is another cam or eccentric H, Operating the lever h' upon its fulcrum h. This lever is provided with the holes 77,2 for connecting it with a shaking-bar I, which is connected with the grates, and by means of the diiferent holes 77,2 in the lever h, to which it may be connected, be given different degrees of motion. This cam-shaft G is set in motion through the medium of the worm-wheel g' and worm Q2, which latter is located on the Vertical shaft Q3, driven, pref-` erably, by the bevel-gears g4 and g5 and the pulley gS, near the top of the boiler-front, from any suitable source of power.

The coal-hoppers J are provided with the feed-slides j, and designed to be filled by hand' with a shovel; but these stokers may be connected by suitable tubes with reservoirs of coal supplied by shoveling, or by endlesschain conveyers or any other suitable means.

The operation of my invention is practically as follows: Coal being placed in the hopper J, and the cam-shaft G being set in rotation, the cam F lifts the pawl E, compressing the spring e', and at the same time, through the medium of the sockets cl on the end of the rocking shaft D, on which the cam F is located, turns the squared ends of the shovelfulcrum shaft c, and causes the face of the shovel to move outward slowly until the front edge of the shovel-face 02 is opposite the inner edge of Ithe delivery-spout b. At this point the quick projection f on the face of the cam F strikes the pawl E and causes the face of the shovel to quickly uncover the opening of the discharge-spout b, allowing, in the short interval of time before the cam F releases the pawl E by passing from under its point, only a small amount of coal to be deposited on the corrugations formed by the lateral proj ections c3 upon the face of the shovel O, and which are prevented 'from falling off entirely by the lip O on the bottom. The point of the cam F having now passed the point of the pawl E, thereby releasing it, the spring e' throws the pawl E downward and causes the shovel O to rotate inward with a quick motion upon its fulcrum, as before described, causing the valve-plate c4 on the rearward part of the shovel Cto close the feed-opening from the hopper, so as to cut off the supply of coal until the next outward oscillation of the shovel. The same motion throws the coal unevenly over the fire-surface, the force with which each particle of coal is thrown depending upon its position on the face of the shovel, the coal upon the upper end of Athe shovel being thrown to the farther end of the furnace, and that upon the lower part of the shovel into the nearest part of the furnace. In selfacting shovels having their fulcrum at the top that part of the coal having greatest motion imparted to it by the lower part of the shovel is thrown into the farther part, and that thrown by the Vupper portion of the shovel i`nto the nearest part of the furnace, the coals crossing each other in their fiight into the furnace, which renders them liable to 'collide and interfere with each other and form a heap near the center of the furnace. By my invention this defective action is entirely done away with, as the coals thrown by my device into the farthest end of the furnace pass entirely above those thrown into' the nearer parts of the furnace in their fiight, owing to their greater Velocity.

The vibrating shovel O may be employed without the corrugations G3, if desired; but I prefer to use the corrugations with the shovel, to prevent the coal sliding too freely to the lower part of the shovel.

If desired, the hopper J and the wall b' of its throat might be removed and the coal dropped upon the shovel O by hand or by any other means when it exposed its face, as hereinbefore described, but I prefer to use the hopper. With the latter construction the valve-plate C4 might also be dispensed with, as it only operates when the hopper-spout -is present.

IOO

Mechanism other than that described may be used to vibrate the shovel and project coal by it into the furnace without departing from the spirit of my invention.

Having fully describ ed my invention, What I claim, and desire to secure 4by Letters Patent,

1. The combination of a furnace provided with an opening in the wall thereof, the vibrating shovel C, pivoted at its bottom and provided with corrugations ca, substantially as described.

2. The combination of a furnace provided with an opening in the wall thereof, the vibrating shovel C, pivoted at its bottom, and provided with a shelf O at its bottom, substantially as described.

3. The combination of the furnace provided with an opening in the wall thereof, the vibrating shovel O, pivoted at its bottom and provided with the valve-plate (34, and the hopper J, placed above the shovel and adapted to supply fuel thereto, substantially as described.

4:. The combination of the furnace provided with an opening in the wall thereof,the vibrating shovel O, pivoted at its bottom, provided with the valve-plate c4 and with the corrugations ca, substantially as described.

5. The combination of the furnace provided 'IIo with an opening in the wall thereof, the vivided with the valve-plate 04 and With a shelf O at its bottom, substa-ntially as described.

6. The combination of a furnace provided With a door-opening in the wall thereof, a door pivoted to the furnace-front and adapted to close said opening and having an opening through itself, and the Vibrating shovel C, pivoted upon the door and adapted to vibrate to and fro through the opening therein and receive and project coal through the opening into the furnace, substantially as described.

7. The combination of the furnace provided with a door-openin g in the Wall thereof, a door pivoted to the furnace-front and adapted to close said openin g and having an opening through itself, the vibrating shovel C,pivoted upon the door and having the squared end c' of its pivot c engaging with the corresponding slot in the rocking shaft D, substantially as descrihed.

8. The combination of the furnace provided with a door-opening in the Wall thereof, a door pivoted to the furnace and adapted to close said opening and having an opening through itself, the vibrating shovel pivoted upon the door and adapted to Vibrate to and fro through said opening and receive and project coal through the same into the furnace, and the hopper J, mounted upon the furnacefront and formed in two parts, one stationary and the other carried by the door, substantially as described.

9. The combination of the furnace provided with a door-opening in the wall thereof, a door pivoted to the furnace-front and adapted to close said opening and having an opening through itself, the vibrating shovel C, pivoted at its bottom, having the squared end of its pivot c' en gaging with the corresponding slot in the rocking shaft D, and the pawl E, springrod e, and spring c', and the rotating cam F, provided With the enlargement f on or near its point, substantially as described.

In testiniony Whereof I have signed my name to this specification, in the presence of two subscribing Witnesses, on this 20th day of April, A. D. 1889.

ISAAC H. DAVIS.

Vitnesses:

FRANoIs H. GRANE, CORNELIUS A. OLIVER. 

